Automatic fuel control



T. .w. CRANE.

. AUTOMATIC FUEL CONTROL;

APPLICATION FILED DEC-21. 1929.

Patented Dec. 20, 1921.

'2 sn'zers-suen I.

momvsrs v.T. W. CRANE.

AUTOMATIC FUEL CONTROL,

APPLICATION FILED DECJII IQZO. A 1,400,868.

Patented Dec. 20, 1921.

ATTORNEYS UNITED STATES PATENT OFFICE.

AUTOMATIC FUEL CONTROL.

Specification of Letters Patent.

Patented Dec. 20, 1921.

Application filed. December 21, 1920. Serial No. 432,351.

To all whom it may con 0am:

Be it known that I, THOMAS WILLIA CRANE, a citizen of the United States, and a resident of Imperial, in the county of Imperial and State of California, have invented certain new and useful Improvements in Automatic Fuel Controls, of which the following is a specification.

My invention is an improvement in automatic fuel controls, and has for its object to provide a two tube system, wherein the fuel tank is connected to the carbureter fuel chamber by an air pipe and'a fuel pipe, the arrangement being such that as fuel is withdrawn from the fuel chamber of the carbureter, air will be admitted to the fuel tank to permit fuel to feed from the tank to the fuel chamber of the carbureter.

Further an important aim of this invention is to provide an automatic fuel control means wherein the vacuum tank and the pipes leading from the vacuum tank to thecarbureter constitute the sole means for maintaining the fuel level in the fuel chamber of the carburetor thereby dispensing with the necessity of employing a float and associated parts. a

In the drawings Figure 1 is a vertical section through one form of the improved system of fuel control.

Fig. 2 is a similar view of the system when used with a different form of fuel tank.

The present embodiment of the invention is shown in Fig. 1 in connection with a Stewart vacuum gasolene system, consisting of a tank having a lower chamber 1 and an upper chamber 2, communicating with the lower chamber 1 by means of an elbow 3, the said elbow having at the outlet end thereof a flap valve 4-.

The chamber 2 is coaxial with the chamber 1 and the stem 8 which is connected. to the float 9 passes through the guide 7 which also forms a by pass for the fuel to the chamber 1. The flap valve 4: on the elbow prevents the return of the fuel from the chamber 1 to the chamber 2 while the latter is being filled by the suction fromthe engine intake manifold. The upper end of the stem.8 is pivoted to one end of a lever 10 pivoted as at 11 to the head 5 which closes the top of the chamber.

The upper chamber has an outlet indicated at 6 to the intake manifold, and a check valve 25 is arranged within the outlet, acting to prevent the return of air to the tank. There is provided also an air vent 2 1 which is controlled by a valve 22. The valve 22 is connected with a stem 23 whose lower end is pivoted to one end of a lever 13. This lever 13 is pivoted at the other end to the head 5, and the valve 26 which controls the connection 6 with the intake manifold is also connected with this lever 13.

A lever 14: is pivoted to the head at the connection of the lever 13 therewith, at one end of the lever 14, and the other end of the said lever 14 is connected by a pair of springs 27 with the remote end of the lever 13. A. link 12 connects the lever 14 intermediate its ends with the lever 10 before mentioned. The upper chamber of the tank is connected by a connection. 15 with the fuel tank. This is the usual construction of Stewart vacuum tank, and the operation is as follows:

hen the engine is in operation, a partial vacuum is created in the upper chamber through the connection 6.- When the suction valve 26 is opened, and the engine is drawing fuel from the main reservoir, the valve 22 which is the atmospheric valve, is closed.

hen the valve 26 is closed, the valve 22 is opened, to connect the tank with the atmosphere, such connection being necessary in order that the fuel may flow past the valve 4: to the lower chamber. It will be noticed that there is-a by-pass 21 which connects the lower chamber at all times with the vent 2 1-.

The improvement consists in connecting the air vent 24: by means of a pipe 18 with the fuel chamber 55 of the carburetor 56. A. pipe 16 leads from the bottom of the lower chamber and opens into the bowl of the carburetor at the top thereof, and alongside the pipe 18.

The pipe 16 extends-into the bowl below the normal level of the fuel, as clearly shown, and the pipe 18 extends into the bowl slightly below the level of the fuel. A cut-off valve 17 is arranged in the pipe 16 adjacent to the tank. A sleeve 19 of larger diameter than the pipe 18 is supported by the said pipe in the bowl, and the sleeve extends some distance below the lower end of the pipe 18. This sleeve is for the purpose of maintaining the level of the fuel within the sleeve free from disturbances due to jar and jolts.

Referring to Fig. 1, it will be seen that the tip of the spray nozzle 20 of the carbureter is at the level of the fuel in the bowl, and at approximately the same level as the lower end of the pipe 18. It will be seen that instead of connecting the air vent as in the Stewart tank, directly with the atmosphere, I connect such vent with the fuel chamber of the carbureter. The connections 16 and 18, together with the check valve 25 are necessary for the successful control of the fuel when my system of fuel control is used with the Stewart vacuum tank, and such connections do not interfere in any way with the usual working of the Stewart vacuum tank.

The check valve 25 is held to its seat by a coil spring as shown, and the fuel cham ber of the carbureter has an air vent indicated at 57. The operation of the above described embodiment is as follows: "When the engine is running, the fuel in the bowl will eventually fall below the level of the lower end of the pipe 18. Air will now pass through the pipe 18 into the main tank, permitting the fuel to flow through the pipe 16 into the bowl of the carbureter to restore the normal fuel level. end of the pipe 18 is sealed by the rising fuel, the passage of air into the tank 1 is interrupted, and the flow of fuel from the tank 1 to the carbureter bowl is checked until air is again admitted to the lower end of the pipe 18.

While the engine is running, the flow of air to the fuel tank and the flow of fuel to the carbureter are practically constant. With the exception of when the filling plug 44 in Fig. 2, is open for filling, the fuel tank, its connections and'connecting pipe must be airtight, and maintained so. The fuel tank should be heavy enough to withstand atmospheric pressure from without so that it will not collapse or vibrate as the fuel is being used by the engine, or through shock or jar.

In the embodiment of the invention shown in Fig. 2, a single tank 28 is provided. This tank has a connection 29 at its top with the intake manifold, and a valve 30 controls the connection. A pipe 31 leads from the bottom of the tank to the bowl of the carbureter 32, opening through the top of the bowl and extending below the fuel level, as shown. A pipe 33 leads from the bowl to the top of the fuel tank, this pipe 33 extending to the fuel level, that is, to the level of the spray nozzle 34, and having the sleeve 35 corresponding to the sleeve 19 of Fig. 1.

The pipe 33 opens through the top of the tank, as before stated, and through a removable head 35, at the center of the said top, and a conical valve 36 cotiperates with the lower end of the pipe. This valve is pivoted to one end of a lever 37, which is piv- As soon as the lower oted at its other end to a bracket 38 depending from the head 35. The pipe 31, before mentioned, connects by means of the union with a nut 39, which is engaged within a casing 40, which forms the valve seat held in a washer 41, secured to the bottom of the tank. The tank has an opening at the washer, and the casing 40 and the nut 39 cotiperate to form an inclosure in which is arranged a valve 42 on the lower end of a stem 43. This stem extends upwardly to the filling plug 44 engaged at the center ofv the head 35, and anut 45 is engaged with the filling plug 44.

A packing nut 46 engages the nut, and the screw 47 is threaded through the nut, the screw having a handle outside of the cap. The inner end of the screw is pointed, or conical, and engages a similarly shaped opening in the upper end of the stem 43, and it will be evident that by turning the screw in the proper direction, the stem may be moved in a direction to close the valves 42 and 36.

The lever 37 before mentioned, is pivoted to this stem with a lost-motion connection, indicated at 48. A coil spring 49 encircles the stem between the lever and a stop 50 on the stem,'the spring acting normally to force the stem downwardly away from the lever. A second coil spring 51 encircles the stem between the bottom of the tank and a stop 52 on the stem, the spring 51 acting normally to close the valves 42 and 36.

In operation, when the fuel in the carbureter bowl falls below the predetermined level, air will be admitted through the pipe 33 to the tank. The fuel will now flow from the tank by way of the pipe 31 to the carbureter bowl, restoring the fuel level. As soon as the levelis restored, the air will be shut ofi from the pipe 33, and the flow of fuel will be stopped. When the screw 47 is turned a few turns to loosen the stem, these springs 49 and 51 will close the valves 36 and 42. The cap 46 is a packing nut.

In order to fill the fuel tank 28 in Fig. 2 the valves 36 and 42 should be first closed by loosening the screw 47 three or four turns so that the spring 51 can close the two valves 36 and 42. The filling plug 44 is then opened and the tank filled, plug 44 is closed and the valve 30 which controls the connection to the intake manifold-is opened for about ten seconds while the engine is running. This creates a partial vacuiun in the tank 28 which prevents the fuel from flowing out until air is admitted through the tube 3. The valve 30 is then closed, and the two valves 36 and 42 are opened by tightening the screw 47 three or four turns which compresses the spring 51 and. opens the valves 36 and 42. The system is then ready to operate until the tank needs to be refilled.

The objectof my improvement in automatic fuel control is to control the flow into the height of the fuel in the carbureter from gravity fuel tanks without the use of a float; float arm; float arm pin; float valve and in some cases other minor parts, that are used to control the height and flow of the fuel in the standard makes of carburetors that are being used at the present time.

The advantages gained are a more sensitive, rapid and positive fuel control which maintains the same fuel height at all engine speeds. Carbureters designed for this fuel system will be cheaper to make, will cost little or nothing to maintain and may be made much smaller, as a large fuel bowl is not needed.

I claim:

1. The combination with a fuel containing vacuum tank, of a carbureter having a fuel chamber, a fuel supply pipe extending from said tank into said fuel chamber and terminating below the level of the fuel in said chamber, an air conducting pipe extending from said tank to said chamber and terminating at approximately the level of the fuel therein, said vacuum tank and said pipes constituting the sole means for maintaining a constant fuel level in the chamber of said carbureter, and means surrounding the air inlet end of said air conducting pipe to prevent the splashing of the fuel adjacent said air inlet pipe.

2. The combination with a fuel containing vacuum tank, of a carbureter having a fuel chamber, a fuel supply pipe extending from said tank into said fuel chamber and below the level of the fuel in said chamber, and an air conducting pipe extending from said tank to said chamber and terminating at approximately the level of the fuel in the tank, said vacuum tank and said pipes constituting the sole means for maintaining a constant fuel level in the chamber of said carbureter.

3. The combination with a fuel containing vacuum tank, of a carbureter having a fuel chamber, a fuel supply pipe extending from said tank into said fuel chamber and below the level of the fuel in said chamber, and an air conducting pipe extending from said tank to said chamber and terminating at approximately the level of the fuel in the tank, said vacuum tank and said pipe constituting the sole means for maintaining a constant fuel level in the chamber of said carburetor, said carbureter being provided with an opening establishing communication between said fuel chamber and the atmosphere.

THOMAS WILLIAM CRANE. 

